1. Field of the Invention
The present invention relates to a light-emitting device including a light-emitting element such as a light-emitting diode element (LED element), more specifically to a light-emitting device including a phosphor plate provided on a light-emitting surface of a light-emitting element.
2. Description of the Related Art
In recent years, as light sources for light-emitting device, light-emitting diode element(s) (hereinafter referred to as LED element(s)) have been widely used. The LED elements started to have been widely used for general lightings, backlights of color displays of various electronic devices, illuminations and so on, because the LED elements can have a longer service life, excellent drive characteristics, more efficient color of light with a smaller size, compared with an old-established light source such as an incandescent lamp.
Recently, there are proposed light-emitting devices configured to emit light emitted from the LED element upward by covering a periphery of the LED element with a reflective white resin (for reference, see JP2010-192629A and JP2007-19096A).
FIGS. 11A to 11D illustrate a manufacturing process of a light-emitting device 100 described in JP2010-192629A.
FIG. 11A illustrates a process in which an LED element 101 is mounted on an upper surface of a substrate 107 through electrically conductive members 106a and 106b, a frame 109 is disposed to surround the LED element 101, and a space between the LED element 101 and the frame 109 is filled with a first light-reflective white resin 104.
FIG. 11B illustrates a process in which a transparent adhesive 103 is applied to an upper surface of the LED element 101 to adhere a light-transmitting member 102 to the upper surface.
FIG. 11C illustrates a process in which the light-transmitting member 102 is adhered to the upper surface of the LED element 101 through the transparent adhesive 103.
FIG. 11D illustrates a process in which a second white resin 105 is dropped on the substrate 107 by a dropping device 108 to cover a periphery of the light-transmitting member 102 and a peripheral side surface by the second white resin 105.
In this way, the light-emitting device 100 is completed by covering the periphery of the LED element 101 with the first white resin 104 and covering a peripheral side surface of the first white resin 104 and a peripheral side surface of the light-transmitting member 102 with the second white resin 105.
FIG. 12 illustrates a light-emitting device 200 described in JP2007-19096A. The light-emitting device 200 includes a case 203 having a hollow 203a, an LED element 201 mounted on a pair of upper electrodes 205a, 205b provided on a bottom surface of the hollow 203a through conductive members 206a, 206b, a light-reflective white resin 204 with which the hollow 203a of the case 203 is filled and a periphery of the LED element 201 is covered, and a sheet-shaped phosphor layer 202 adhered to an upper surface of the LED element 201.
The white resin in each of the light-emitting devices 100 and 200 reflects light emitted from the LED element 101, 201 to be directed to the upper surface side of the light-emitting device, and has a function to enhance light-harvesting property and light-emitting effect.
As the white resin, it is possible to use a material in which a reflective filler such as oxidized titanium, silica dioxide, zirconium dioxide, alumina, boron nitride and so on is mixed in a coating material such as silicone resin, epoxy resin, acryl resin and so on.
However, in the light-emitting devices 100 and 200 disclosed in JP2010-192629A and JP2007-19096A, the white resin 104 (204) is filled at the side surface side of the LED element 101 (201) mounted on the substrate 107 or the case 203 in a state where the light-emitting surface of the LED element 101 (201) is exposed, and after the white resin 104 (204) is hardened, the light-transmitting member 102 or the phosphor layer 202 is adhered to the light-emitting surface of the LED element 101 (201). Consequently, there is possibility that the white resin 102 (204) is attached to the light-emitting surface of the LED element 101 (201). If the white resin 102 (204) is attached to the light-emitting surface, a process to remove the white resin is required, there is a problem in that productivity is reduced.
Furthermore, in the light-emitting devices 100 and 200, because the light-transmitting member 102 or the phosphor layer 202 is adhered to the light-emitting surface of the LED element 101 (201), there is a possibility that the light-transmitting member 102 or the phosphor layer 202 is detached from the light-emitting surface by the deterioration and so on of the adhesive.
In addition, because the light-transmitting member 102 or the phosphor layer 202 has a thickness, there is possibility that a yellow ring occurs.